Diagnostic systems detect and quantify a signal disturbance when a disturbance exceeds critical parameters of the diagnostic system. A high performance Analog-to-Digital Converter (ADC) with signal post processing can detect analog samples of a signal, convert the analog samples to digital values, and perform, using digital circuitry, signal post-processing on the digital values to detect a signal disturbance in the signal. The diagnostic system can be set with a sampling frequency that balances a capability to detect higher frequency signal disturbances and a cost of the diagnostic system.